Lucanthone and hycanthone are thioxanthenones which are schistosomicidal drugs and have shown carcinostatic activity in experimental animal tumors. They intercalate between base-pairs of DNA and it is believed that this property may be responsible for the cytotoxic effects of the drugs. However, in vivo activity against leukemia L-1210 can be antagonized by co-administration of an inhibitor of microsomal oxidation. We plan to prepare a possible biotransformation product of lucanthone which we think may be the active in vivo form. Other lucanthone analogs will be synthesized which we hope will have increased potency as intercalating and antitumor agents. We will be guided in our synthetic efforts by an intensive study of models of DNA-thioxanthenone complexes. Quantum mechanical calculations of the stabilization and activation energies will be made with MINDO/2, etc., semi-empirical techniques on a series of substituted anthraquinones and thioxanthenones. Mechanisms of the kinetics will be postulated and trends in the association constants for the intercalator with the receptor site will be calculated and correlated to biological activity. Some aminoalkylaminoanthraquinones are intercalating agents but their antitumor activity has not been evaluated. We intend to prepare a series of substituted anthraquinones and have them tested as antitumor agents. The biological activity will be correlated with their intercalating action. The compounds to be prepared are distantly related structurally to adriamycin but will probably behave similarly as intercalators.